I recently repaired two hydraulic cylinders on my 1955 model Allis Chalmers WD45.
Information I could find on this procedure was weak, so I have added this here for others who may find it useful.
Allis-Chalmers WD-45 Hydraulic Cylinder Rebuild Kit
1. Raise Lift Arms and support or block them in the up position using something such as a wooden block or board.
2. Remove the cotter pin that secures the ram to the rear lift arm at the rear of the cylinder assembly. (Do not remove the fork pin at this time.)
3. Remove the cotter pin that secures the ram bottom cap to the tractor?s support bracket stud bolt at front of the cylinder.
4. Loosen the hydraulic line fitting on the cylinder assembly from the hose (right angle adapter) coming from the pump. A small amount of fluid will flow and can be stopped reasonably by lifting the hose above the pump. Tie it up with a piece of twine or string to keep from siphoning and losing too much fluid.
5. Remove the rear lift arm pin and drop the rear of the cylinder assembly.
6. Remove the cylinder assembly from the support bracket.
7. Compress the Ram into the cylinder assembly and catch fluid into a pan or tub as it is pushed out the cylinder assembly?s hydraulic line fitting.
8. At the workbench, hold the cylinder assembly in a large vice around the Ram cylinder. Do a rough start cleaning to remove grease and crud off the external parts, including the Ram.
9. Loosen the Gland Nut (don?t totally remove it yet, to keep dirt out). Then using two pipe wrenches, and likely two long cheater bar pipes, unthread the cylinder assembly at the joint between the Guide and Ram cylinder. This is the joint between the big tube and little tube towards the end of the cylinder assembly with the ram sticking out of it. (see Fig AC-176 on pg 95 of I&T Service?s Shop Manual AC-11 for Allis-Chalmers WD-45. Catch the remaining fluid in a pan or tub, as it will still have about a cup inside.
10. Check the Ram to see if there are any burs or debris around the hole that the lift arm pin goes through that could damage the inside of the cylinder Guide or the internal Bushings or Bushing Spacer. If so, file them down, clean and smooth it out so the Ram can move freely through the cylinder assembly.
11. Remove the Gland Nut from the top end and push the Ram out the bottom of the Ram Guide tube, (it?s not necessary to remove the snap ring from the ram, so don?t do it!).
12. Remove the old packing (5 pieces) from the top end of the Guide tube. Usually, this can be done with just your fingers. If it?s encrusted, you may need to pry with a tool such as a flat blade screwdriver to first get out the .275 seal, then the others will be easy. If there is a lot of debris or pieces of rust inside, you may want to also drive out the Bushings and Bushing Spacer. To start this, drive on the edge of the Bushing Spacer from the bottom end and push the parts out the top.
13. Clean all of the parts. Use an appropriate solvent such as carb/choke or brake cleaner. Wipe it all down and inspect and remove any chunks or rust.
14. Reinstall the Bushing, Bushing Spacer, and Bushing in order, if they were taken out.
15. One at a time, install the five pieces of the hydraulic cylinder packing kit (Steiner Tractor Parts, Inc. ; part number ACS3464, will need two to do both cylinders). Take care to install these chevron type packing seals into the plunger guide with the open end of the V towards the oil supply. Also, verify they are in the size order indicated with the manufactures instruction sheet.
16. Reinstall the Gland Nut, finger tight snug only. It may require a light tap with a hammer to get the seals compressed enough to grab some threads.
17. Push the Ram back into the assembly starting from the bottom end of the Guide tube. Take care to not damage the internal Bushings, Bushing Spacer, or packing seals.
18. Reassemble the Ram Guide tube to the Cylinder tube. Tighten sufficiently with pipe wrenches and use pipe dope if you think it?s necessary to prevent leakage.
19. Reinstall the cylinder assembly onto the tractor?s support bracket stud bolt. (Don?t connect to the rear link yet.)
20. Compress the Ram into the cylinder to push out as much air as possible before connecting to the hydraulic hose.
21. Loosely connect the hydraulic line fitting on the cylinder assembly to the hose (right angle adapter) coming from the pump. Get it snug enough to draw fluid, but not too tight to strain the hose when you lift the cylinder assembly to connect the rear.
22. Draw out the Ram from the cylinder, (drawing fluid into the cylinder tubes). Attach it in the yolk of the rear lift arm using the rear lift arm pin.
23. Adjust the position of the hydraulic hose to ensure it?s a straight fit and tighten the cylinder assembly?s hydraulic fitting to the pump hose right angle adapter.
24. Reinstall the cotter pins to secure the front and rear.
25. Start the tractor and raise the lift arms to their full up position. Allow fluid to bleed out around the Gland Nut while the cylinder is in the fully extended position. This purges air from the line and cylinder assembly.
26. Tighten the Gland Nut sufficiently to stop leakage, but not overly tight.
27. Raise and lower the arms several times to inspect for leakage.
28. Shut off the tractor.
29. Wipe it all down to remove any oil and check the level of the transmission and hydraulic pump reservoir. Refill as necessary using general-purpose tractor hydraulic fluid, (with lift arms in the up position).
30. You?re done! ?. Now go do the other side, because it likely needs it too?.
Information I could find on this procedure was weak, so I have added this here for others who may find it useful.
Allis-Chalmers WD-45 Hydraulic Cylinder Rebuild Kit
1. Raise Lift Arms and support or block them in the up position using something such as a wooden block or board.
2. Remove the cotter pin that secures the ram to the rear lift arm at the rear of the cylinder assembly. (Do not remove the fork pin at this time.)
3. Remove the cotter pin that secures the ram bottom cap to the tractor?s support bracket stud bolt at front of the cylinder.
4. Loosen the hydraulic line fitting on the cylinder assembly from the hose (right angle adapter) coming from the pump. A small amount of fluid will flow and can be stopped reasonably by lifting the hose above the pump. Tie it up with a piece of twine or string to keep from siphoning and losing too much fluid.
5. Remove the rear lift arm pin and drop the rear of the cylinder assembly.
6. Remove the cylinder assembly from the support bracket.
7. Compress the Ram into the cylinder assembly and catch fluid into a pan or tub as it is pushed out the cylinder assembly?s hydraulic line fitting.
8. At the workbench, hold the cylinder assembly in a large vice around the Ram cylinder. Do a rough start cleaning to remove grease and crud off the external parts, including the Ram.
9. Loosen the Gland Nut (don?t totally remove it yet, to keep dirt out). Then using two pipe wrenches, and likely two long cheater bar pipes, unthread the cylinder assembly at the joint between the Guide and Ram cylinder. This is the joint between the big tube and little tube towards the end of the cylinder assembly with the ram sticking out of it. (see Fig AC-176 on pg 95 of I&T Service?s Shop Manual AC-11 for Allis-Chalmers WD-45. Catch the remaining fluid in a pan or tub, as it will still have about a cup inside.
10. Check the Ram to see if there are any burs or debris around the hole that the lift arm pin goes through that could damage the inside of the cylinder Guide or the internal Bushings or Bushing Spacer. If so, file them down, clean and smooth it out so the Ram can move freely through the cylinder assembly.
11. Remove the Gland Nut from the top end and push the Ram out the bottom of the Ram Guide tube, (it?s not necessary to remove the snap ring from the ram, so don?t do it!).
12. Remove the old packing (5 pieces) from the top end of the Guide tube. Usually, this can be done with just your fingers. If it?s encrusted, you may need to pry with a tool such as a flat blade screwdriver to first get out the .275 seal, then the others will be easy. If there is a lot of debris or pieces of rust inside, you may want to also drive out the Bushings and Bushing Spacer. To start this, drive on the edge of the Bushing Spacer from the bottom end and push the parts out the top.
13. Clean all of the parts. Use an appropriate solvent such as carb/choke or brake cleaner. Wipe it all down and inspect and remove any chunks or rust.
14. Reinstall the Bushing, Bushing Spacer, and Bushing in order, if they were taken out.
15. One at a time, install the five pieces of the hydraulic cylinder packing kit (Steiner Tractor Parts, Inc. ; part number ACS3464, will need two to do both cylinders). Take care to install these chevron type packing seals into the plunger guide with the open end of the V towards the oil supply. Also, verify they are in the size order indicated with the manufactures instruction sheet.
16. Reinstall the Gland Nut, finger tight snug only. It may require a light tap with a hammer to get the seals compressed enough to grab some threads.
17. Push the Ram back into the assembly starting from the bottom end of the Guide tube. Take care to not damage the internal Bushings, Bushing Spacer, or packing seals.
18. Reassemble the Ram Guide tube to the Cylinder tube. Tighten sufficiently with pipe wrenches and use pipe dope if you think it?s necessary to prevent leakage.
19. Reinstall the cylinder assembly onto the tractor?s support bracket stud bolt. (Don?t connect to the rear link yet.)
20. Compress the Ram into the cylinder to push out as much air as possible before connecting to the hydraulic hose.
21. Loosely connect the hydraulic line fitting on the cylinder assembly to the hose (right angle adapter) coming from the pump. Get it snug enough to draw fluid, but not too tight to strain the hose when you lift the cylinder assembly to connect the rear.
22. Draw out the Ram from the cylinder, (drawing fluid into the cylinder tubes). Attach it in the yolk of the rear lift arm using the rear lift arm pin.
23. Adjust the position of the hydraulic hose to ensure it?s a straight fit and tighten the cylinder assembly?s hydraulic fitting to the pump hose right angle adapter.
24. Reinstall the cotter pins to secure the front and rear.
25. Start the tractor and raise the lift arms to their full up position. Allow fluid to bleed out around the Gland Nut while the cylinder is in the fully extended position. This purges air from the line and cylinder assembly.
26. Tighten the Gland Nut sufficiently to stop leakage, but not overly tight.
27. Raise and lower the arms several times to inspect for leakage.
28. Shut off the tractor.
29. Wipe it all down to remove any oil and check the level of the transmission and hydraulic pump reservoir. Refill as necessary using general-purpose tractor hydraulic fluid, (with lift arms in the up position).
30. You?re done! ?. Now go do the other side, because it likely needs it too?.
